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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Road and Drainage Plan Review
Project title: Whittington — Phase B
Project file number: SUB- 2014 -00193
Plan preparer:
Dominion Engineering & Design, LLC
Owner or rep.:
Stanley Martin Homes
Plan received date:
24 November 2014
(Rev. 1)
20 February 2015
(Rev. 2)
30 June 2015
(Rev. 3)
27 August 2015
(Rev. 4)
14 October 2015
(Rev. 5)
23 November 2015
Date of comments:
8 January 2015
(Rev. 1)
30 March 2015
(Rev. 2)
5 August 2015
(Rev. 3)
22 September 2015
(Rev. 4)
4 November 2015
(Rev. 5)
25 November 2015
Reviewers:
Justin Deel, Glenn Brooks
This plan has adequately addressed the below comments and is approved. You may contact Ana Kilmer
(Albemarle County Department of Community Development) at ext. 3246 for further information on
bonding procedures,
1. Provide accurate existing topography (Ex. Phase A, existing Kendra Street grading) on plans as
well as Existing Conditions sheet. Provide more existing topography labels on plans for
readability. For example, Sheet RP5 has none, and please show all proposed contours' tie -in with
existing contours (Ex. RP6).
(Rev. 1) Comment addressed.
2. Several existing and proposed elevations shown along the horizontal axes of your profiles are
incorrect or do not match what is shown. Please correct.
(Rev. 1) Comment addressed.
3. Please label streets public or private.
(Rev. 1) Comment addressed.
4. Show and detail all entrance improvements on Rt. 631. The plan seems to indicate widening on
the public road, but no improvements are detailed; turn lanes, sight -line grading, turn tapers, radii,
pavement edge, sections and tie -in, entrance type designations, etc.
(Rev. 1) Comment addressed.
5. Show pavement and right -of -way widths for existing streets.
(Rev. 1) Comment addressed.
6. Show stationing at a 50' minimum on plans and profiles.
(Rev. 1) Comment addressed.
7. Show and label all signs; stop signs, street name signs, and speed limit signs are the minimum.
Engineering Review Comments
Page 2 of 5
(Rev. 1) Comment addressed.
8. Please label street edge of pavement or curb radii at all intersections or turnarounds.
(Rev. 1) Comment addressed.
9. The drainage computations could not be followed. The inlet comps on sheet 19 appear to be for
curb and gutter, when all roads on this plan are rural sections. The SCC computations are by
station, which cannot be read on the drainage area maps. The line weights for drainage divides are
not all legible. The map for pipe runs does not have the pipe runs, and is too small to be legible.
Provide clear drainage area maps, showing acreage, hydrologic coefficient, and time of
concentration for each drainage area.
(Rev. 1) Comment not adequately addressed. Please provide hand computations if your
software does not allow for rural sections. See VDOT Road Design Manual.
(Rev. 2) Comment addressed.
10. Provide traffic generation and distribution summary (ADT) and pavement designs.
(Rev. 1) Comment addressed.
11. Provide typical sections for proposed channels with location references.
(Rev. 1) Comment addressed.
12. Show critical slopes on your plans.
(Rev. 1) Comment not addressed. Please show critical slopes on your design plans so that we
can discern what areas are being affected. Please show slopes that are 25% or greater. We need to
be able to see the whole picture to ensure compliance with Proffer 4. See Comment 14 below.
(Rev. 2) Comment not addressed.
(Rev. 3) Comment addressed.
13. Pipe outfalls are too steep, and outlet velocities too high. Provide step down manholes to reduce
steepness and velocity. Provide channel adequacy demonstrations at each outfall.
(Rev. 1) Comment addressed.
14. The road plan needs to reflect grading on lots which will tie into road grading, as depicted on the
overlot grading plan and erosion and sediment control plan.
(Rev. 1) Comment not addressed. Please show lot grading on road plans with accompanying
road profiles.
(Rev. 2) Comment addressed.
15. Show all utility line crossings in the drainage profiles. Show all existing and proposed culverts.
(Rev. 1) Comment addressed.
16. Lots 5, 13 and 76 have too much stream buffer within the lots to be reasonably enforced. Please
reduce the size of these lots so that stream buffers are not within the lot area as much as possible.
The ordinance allows up to 50 feet of the landward side of stream buffers to be disturbed with
mitigation, and this should be the guideline to follow.
(Rev. 1) Comment not addressed. These lots appear largely unchanged relative to percentage of
the lot in the WPO buffer.
(Rev. 2) Comment addressed.
17. Provide typical driveway details for the roads. Specify driveway culvert sizes and locations with
supporting computations. The minimum size should be 15" dia. This will necessitate a revision to
the typical ditch sections to provide adequate cover, moving the ditch away from the shoulder.
Where long runs of ditch are designed (such as at Kendra sta. 34 to 17) a culvert diameter greater
than 15" will likely be necessary, and this should be clearly detailed.
(Rev. 1) Comment partially addressed. Please provide more detail on your driveway culvert
sizing calculations table. Is your "depth of flow" within the 15" pipe or are you using the channel
geometry to calculate depth of flow and then providing a pipe diameter that exceeds these depths?
You are picking up over 7 cfs going from Lot 7 to Lot 6 from the existing cross - drain. Although
you're calling for a wider channel here, it's still that much more flow going into the same 15"
pipe. Also, how are you addressing the flow from the cross -drain going into Lot 6? The typical
Engineering Review Comments
Page 3 of 5
SCC detail on RP 18 calls for a depth of 12" (2:1). Your typical road section shows a 3:1 slope.
Please clarify. You have a gap from 22 +00 to 23 +00 on your SCC table. Please correct.
(Rev. 2) Comment not fully addressed. Please demonstrate adequate cover for the proposed 18"
& 24" culverts in an 18" ditch. The PE -1 detail in Sheet RP 17 appears to call for atleast 9" of
cover; how is this possible while maintaining a 3:1 slope? Your response indicates that the
roadside ditch has been shifted, as appropriate, to direct flow to the culverts but this does not
appear to be reflected on the plans.
Please show the existing culvert to be abandoned in the profile.
(Rev. 3) Comment not addressed. Driveway culvert profiles have been provided on sheet RP 17
showing that a minimum 9" cover is being achieved; however, all of the invert-out elevations and
most of the invert-in elevations on the profiles are below the ditch elevations at the invert locations
on the plans. Adequate cover cannot be demonstrated by burying the pipe inverts below the ditch
grade. Grading and location of the driveway culverts must be shown accurately so that the slope
and depth of the ditch can be accurately reviewed. Providing the PE -1 detail for the contractor to
interpret the applicability and degree of offset for each of the 17 culverts will very likely result in
severe slopes and "holes" around the driveways. Please address. Reflect all changes on the
overlot grading plan as well.
(Rev. 4) Comment not fully addressed. Profiles demonstrating adequate cover for driveway
culverts at lots 6 & 7 are not provided. Please provide, as these lots show proposed 18" culverts.
The proposed grading around the driveway culverts at lots 18 & 19 are exactly what this comment
was intended to prevent, where the culvert creates 2 -3' holes. How will this be stabilized? The
hole created by the lot 19 culvert ties directly into the 2:1 grading you're showing for lot 18.
Proffer 4d states that slopes graded on lots shall not exceed 3:1 unless planted with low -
maintenance ground cover (not grass). Please note this throughout the plans where 2:1 slopes are
proposed.
(Rev. 5) Comment addressed.
18. Detail inlet grading on slopes where grate inlets are placed to intercept ditch flow on grade. The
ditch will need to be wider, and a berm will be required to terminate the ditch at these points.
Examples are structures 15, 8 -9.
(Rev. 1) Comment not addressed. Please show proposed inlet grading tied in to existing or other
proposed grade lines on road plans. Your typical detail is not adequate in showing how the inlet
grading will tie into other proposed grading.
(Rev. 2) Comment addressed.
19. Provide guard rail at hazard areas, culverts, and where a steep slope leaves the roadway edge.
Examples are Kendra sta. 16 -18, sta. 31 -34, and cul -de -sac, Cottontal Way sta. 12 -14, 18 -22, 24-
26, etc.
(Rev. 1) Comment addressed.
20. VDOT approval is required.
(Rev. 1) Comment acknowledged.
21. Planning Division approval is required. Comments from Ellie Ray are attached
(Rev. 1) See attached comments.
(Rev. 2) Comments not addressed. Planning comment letter attached.
(Rev. 3) Planning comments will be forwarded once they are received.
(Rev. 4) Planning comments still pending.
(Rev. 5) Comment addressed.
22. Fire & Rescue Department approval is required. Comments from Robbie Gilmer are included
below;
(Rev. 1) Comment acknowledged.
Engineering Review Comments
Page 4 of 5
Revision 1 comments
23. The proposed emergency access from Route 631 may need to be an amendment to Phase A, not
part of Phase B. Please consult with County Engineer upon his return to the office April 6, 2015.
(Rev. 2) Comment addressed.
24. You do not appear to be in compliance with Proffer 4g on many lots. Please provide an area in
front of each proposed garage or proposed parking space on each lot that is no less than 18 feet
and not steeper than 8 percent.
(Rev. 2) Comment addressed.
Revision 2 comments
25. The phasing (B1 -B4) from the first submission has been added to your site overview sheet. Are
you going back to this phasing plan?
(Rev. 3) Comment addressed.
26. As a general rule, the County prefers not to see pipes going down in size downstream. Structure 4
appears to be receiving flow from a 24" driveway culvert and a 15" crossdrain. All that is then
going to an 18" HDPE. Please address this.
(Rev. 3) Comment addressed.
Revision 3 Comment:
27. Please provide an exhibit or other evidence that confirms compliance with Proffer 4c, which states
that grading will be shown to assure that surface drainage can provide adequate relief from the
flooding of dwellings in the event of a storm sewer failure. It is difficult to see how some of the
home sites at the ends of the cul -de -sacs, particularly Cottontail Way, would not be significantly
impacted in the event that the adjacent storm sewer(s) fail. Please examine all home sites,
including those in Phase A, that could potentially be impacted.
(Rev. 4) Comment not addressed. The provided analysis (profiles) shows that the 100 year
storm does not flood the dwellings with a fully functioning storm sewer. This does not address the
proffer. Show that there is adequate overland relief to prevent the flooding of dwellings in the
event of a storm sewer failure, particularly at these critical locations at the ends of the cul -de -sacs.
Concerning the Phase A lots, you say that analysis will be provided under separate cover. What
cover will that be? The analysis should be included in this plan as the proposed improvements
with this plan potentially impacts existing approved some sites in Phase A. Please provide.
(Rev. 5) Comment addressed.
28. Provide analysis for the existing 24" HDPE, adjacent to Lot 49, that is to remain in place.
(Rev. 4) Comment addressed.
29. Provide street name in plan view, Sheet RP 15.
(Rev. 4) Comment addressed.
The following comments quoted from Robbie Gilmer (Fire & Rescue) will need to be addressed prior to
approval:
1. Cul -de -sac shall be 96 ft EP/EP.
2. Add the symbol for fire hydrant between lot 26 & 27.
3. Clarify if the hydrant between lots 24 & 25 is a proposed hydrant or not.
4. Clarify the hydrant location at lots 20 and 21.
Engineering Review Comments
Page 5 of 5
5. Hydrant spacing shall be no more than 500 ft per travelway.
6. VSWFPC- D107.1 One- or two- family dwelling residential developments. Developments of one -
or two- family dwellings where the number of dwelling units exceeds 30 shall be provided with
two separate and approved fire apparatus access roads, and shall meet the requirements of Section
D104.3.
Exceptions:
1. Where there are more than 30 dwelling units on a single public or private fire apparatus
access road and all dwelling units are equipped throughout with an approved automatic
sprinkler system in accordance with Section 903.3.1.1, 903.3.1.2 or 903.3.1.3 of the
International Fire Code, access from two directions shall not be required.
2. The number of dwelling units on a single fire apparatus access road shall not be increased
unless fire apparatus access roads will connect with future development, as determined by
the fire code official.
(Rev. 1) Comments addressed. Robbie Gilmer: "Based on plans dated 10/7/15, no comments or
objections."
Please consult the road plan and drainage plan checklists at the document center on the Albemarle County
website for further details. Due to the incomplete nature of this plan, further comments will likely be
necessary upon revision. It is expected that the grading and drainage layout will change due to comments
on the erosion control and stormwater management plans, which have asked that the existing topography
and drainage divides be more closely followed. (Examples on these plans would be where ditches are
shown on the low side of road sections. The contractor will expect these areas to sheet flow downslope,
away from the road, and not build a ditch, which is reasonable. It will be difficult to prevent this.)
(Rev. 2) Comment addressed.
Please address attached VDOT comments. Comments from Planning and ACSA will be forwarded as they
are received. Note that final approval will come only after receiving approval recommendations from all
parties.
File: SUB201400193 Whittington Ph B Road Plan R5.doc